I don't worry about the cost very much because I like to use whole grains and, if possible, organic products. I also try to add in veggies which means that in most cases I buy them freeze-dried.

I do buy stuff in bulk when possible and try to do most of my dehydrating in the winter (who wants to heat up the house with a dehydrator when it's 95*F outside?). I did a lot of price comparison this year among several purveyors of freeze dried food. In nearly all cases, Just Tomatoes came out the winner for fruits and veggies, and Packit Gourmet for freeze-dried meats. In fact, I found that the prices for the large containers of Packit Gourmet beef and chicken were basically the same as buying canned chicken (non-pressure-cooked chicken usually becomes chicken jerky in the dehydrator) or extra-low-fat ground beef and dehydrating them--and a lot less work!

I cook rice (the brown variety) and other grains in broth (chicken, beef or, mostly, vegetable) before dehydrating them, which enhances their flavor. Both cheaper and a lot better-tasting than "Minute" or "Uncle Ben's."

I also cook bean and lentil dishes and dehydrate them. I also put together meals of cous-cous (no precooking-dehydration needed), freeze-dried veggies, TVP and plenty of seasoning. These can be thrown together at the last minute.

I use a lot of nuts and dried fruit for snacks/lunch. For trips of a week or more, I use freeze-dried fruit to save weight. For shorter trips, I get bulk regular dried fruit such as sold in the health food sections of many supermarkets.

IMHO, it's most important that your food taste good. If it doesn't, you won't eat it. Uneaten rehydrated food in your garbage weighs more than the dehydrated food you've carried in! Variety is important also, for this very reason. Eating the same thing every day will pall on you by Day 3 or 4!